Xiao-Jing Wang

Lycojaponicumins A-C, three alkaloids with an unprecedented skeleton from Lycopodium japonicum.

Lycojaponicumins A-C (1-3), three trace alkaloids isolated from Lycopodium japonicum, represent a unique heterocyclic skeleton formed by the new linkage C4-C9. Notably, lycojaponicumins A and B (1 and 2) are the first examples of natural products possessing a 5/5/5/5/6 pentacyclic ring system with a 1-aza-7-oxabicyclo[2.2.1]heptane moiety. These structures were elucidated by spectroscopic methods and X-ray diffraction analysis. A plausible biogenetic pathway was proposed.

Lycojaponicumins D and E: Two New Alkaloids from Lycopodium japonicum

Two new alkaloids, lycojaponicumins D (1) and E (2), were isolated from the club moss Lycopodium japonicum. Their structures were elucidated by spectroscopic methods, calculated ECD, CD experiments and X-ray diffraction analysis. Lycojaponicumin D (1) possesses an unprecedented 5/7/6/6 tetracyclic skeleton formed by an unusual C3-C13 linkage, which is first reported in Lycopodium alkaloids. The plausible biogenetic pathway of 1 is proposed.

Five new fawcettimine-related alkaloids from Lycopodium japonicum Thunb.

Five new trace alkaloids with fawcettimine-related structures (1-5), i.e., 6-hydroxyl-6,7-dehydrolycoflexine (1), 6-hydroxyl-6,7-dehydro-8-deoxy-13-dehydroserratinine (2), together with three known ones (6-8), were isolated from the club moss Lycopodium japonicum Thunb. Their structures were elucidated by extensive NMR spectroscopic analysis, HRESIMS, CD and comparison with known ones. Compounds 1 and 2 are characterized by the enol moiety that is rarely reported in Lycopodium alkaloids, and Compound 5 is the second example of Lycopodium alkaloids with a C-16-C-4 linkage. A plausible biogenetic pathway for the isolates was proposed.

Prenylated C6-C3 compounds from the roots of Illicium henryi.

Eleven prenylated C(6)-C(3) compounds, illihenryifunones A, B (1, 2), illihenryifunol A (3), illihenryipyranol A (4), illihenryiones A-G (5-11), and three known prenylated C(6)-C(3) compounds (12-14), were isolated from the roots of Illicium henryi. Structures of 1-11 were elucidated by spectroscopic methods including NMR, HRESIMS, and CD. The absolute configuration of the 11,12-diol moiety in 5 was determined by observing its induced circular dichroism after addition of Mo(2)(OAc)(4) in DMSO. The absolute configuration of C-11 in 4 was determined as S based on the Rh(2)(OCOCF(3))(4)-induced CD data; the absolute configuration of 3 was determined as R by comparison of its experimental and calculated electronic circular dichroism (ECD). The antioxidant activities of compounds 1-14 were also evaluated. Compound 4 exhibited strong antioxidant activity with an IC(50) value of 2.97±1.30 μM, whereas compounds 3 and 8 showed antioxidant activities with IC(50) values of 44.36±0.30 and 48.00±2.01 μM, respectively.

Pierisketolide A and Pierisketones B and C, Three Diterpenes with an Unusual Carbon Skeleton from the Roots of Pieris formosa

Pierisketolide A (1) and pierisketones B and C (2 and 3), three diterpenes with an unusual A-homo-B-nor-ent-kaurane carbon skeleton, were isolated from the roots of Pieris formosa. Their structures were characterized by a series of spectroscopic methods, X-ray diffraction, and electronic circular dichroism (ECD). Pierisketolide A (1) exhibited an analgesic effect with a 45% writhe inhibition rate at a dose of 10.0 mg/kg. The plausible biosynthetic pathways of 1-3 are proposed.

Sesquiterpenes from the roots of Illicium jiadifengpi.

Two new sesquiterpenes (1, 2) and two new sesquiterpene glycosides (3, 4) with a seco-prezizaane skeleton, three new allo-cedrane sesquiterpene glycosides (5-7), and a new acorane sesquiterpene (8) as well as 15 known analogues were isolated from the roots of Illicium jiadifengpi used for the treatment of rheumatoid arthritis. The structures of these compounds were elucidated by extensive spectroscopic analysis and chemical methods. The absolute configurations of compounds 5-7 were confirmed by CD experiments. The configuration of compound 8 was assigned by single-crystal X-ray crystallographic analysis and CD experiments. Compounds 4, 6, 7, 14, and 23 showed moderate antiviral activities against Coxsackie virus B3, and all compounds were inactive when evaluated for their cytotoxic activities against five human tumor cell lines and neuroprotection.

Novel sesquiterpenoid glycosides and sesquiterpenes from the roots of Illicium henryi.

Seven new sesquiterpenoid glycosides, consisting of one thapsan-type (1), two capnellane-type (2 and 3), four floridanolide sesquiterpene glycosides (4-7), and one new azulene-type sesquiterpene (8), along with six known sesquiterpenes (9-14) were isolated from the roots of Illicium henryi. The structures of 1-8 were elucidated by extensive spectroscopic analyses and chemical methods. The absolute configurations of 1, 2, and 8 were determined based on Rh2(OCOCF3)4-induced CD, Mo2(OAc)4-induced CD data, and calculated electronic circular dichroism (ECD), respectively. Compound 1 was found to exhibit weak neurotoxicant activity.

Oleanane-type triterpene saponins and cassaine-type diterpenoids from Erythrophleum fordii.

Phytochemical investigation of the EtOH extract of the leaves of Erythrophleum fordii led to the isolation of two oleanane-type triterpene saponins (1-2) and five cassaine-type diterpenoids (4-8) along with one known methyl 3 β-hydroxy-erythrosuamate (3). Their structures were established by extensive NMR, as well as ESI-MS analyses and acid hydrolysis. Biological evaluation of compounds 3- 8 against five human cancer cell lines revealed that compounds 5-7 exhibited potent cytotoxic activity with IC₅₀ values ranging from 1.51 to 8.68 µM.

Biological and chemical guided isolation of 3,4-secograyanane diterpenoids from the roots of Pieris formosa

Seventeen new 3,4-secograyanoids (1–17), together with seven known compounds (18–24), were isolated from the roots of Pieris formosa. Their structures with absolute configurations were characterized by a series of spectroscopic methods and X-ray diffraction. Compounds 1, 2, 4–8, 10–13, and 16–24 exhibited significant analgesic activity at 5.0 mg kg−1 (ip) compared to vehicle-injected mice (p < 0.05). In particular, compounds 16 and 17 showed highly potent activities with inhibition rates of 63.5% and 69.9%, respectively.

Illisimonin A, a Caged Sesquiterpenoid with a Tricyclo[5.2.1.01,6]decane Skeleton from the Fruits of Illicium simonsii

Illisimonin A, an unprecedented sesquiterpenoid with a tricyclo[5.2.1.01,6]decane skeleton, was isolated from the fruits of Illicium simonsii. The structure and absolute configuration of 1 were determined using extensive spectroscopic evidence and electronic circular dichroism (ECD) calculations. It was determined that 1 possesses a caged 2-oxatricyclo[3,3,0,14,7]nonane ring system fused to a five-membered carbocyclic ring and a five-membered lactone ring. A plausible biogenetic pathway for 1 was proposed, and 1 showed neuroprotective effects against oxygen-glucose deprivation (OGD)-induced cell injury in SH-SY5Y cells with an EC50 value of 27.72 μM.